function insertSort(arr) {
    for(let i = 1; i < arr.length; i++) {
        let key = arr[i]
        let j = i - 1
        while(j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j]
        }
        arr[j + 1] = key
    }
    return arr
}